Wrong prop for '57 johnson 18hp?

[jbjennings]

Guys, I posted earlier my speed on my 18hp (about 22mph). My "new" '58 evinrude 18hp will go about 24.6 mph and feels way more powerful. I guess I could just switch props and find out, but was wondering anyone has any idea just by looking at it if the prop on my johnson is obviously a prop for a different horsepower motor? The powerhead on the johnson doesn't seem to rev up more than normal, just doesn't have speed or power like the evinrude. The evinrude does seem to have a LOT less wear than the johnson, but the johnson still runs good. I'm attaching a pic of the props to see what you think.
thanks,
JBJ

 

[jbjennings]

Re: Wrong prop for '57 johnson 18hp?

Forgot to post my pic of props. Here goes:

 

[F_R]

Re: Wrong prop for '57 johnson 18hp?

They are both "correct" props. The Johnson has the semi-weedless, that's all. Try switching and report back so we all know the difference.

 

[1730V]

Re: Wrong prop for '57 johnson 18hp?

Yup, the prop on the right is weedless and will not perform like the one on the left.

 

[samo_ott]

Re: Wrong prop for '57 johnson 18hp?

Yep, I have both on my 18's also. They should be 9.25 x 11 and stamped on the prop.

 

[wbeaton]

Re: Wrong prop for '57 johnson 18hp?

They look original, however, either one could have been replaced with a 10 hp prop, which is slightly lower in pitch. I have a 1953 Evinrude 15 hp with the original 9 x 11 weedless prop and a 1954 Evinrude 15 hp with a weedless prop from a "newer" 10 hp, which I'm guessing is about 8.5 x 8.5. I get about the same results as you, but the lower pitch moves my boat faster.

I can't tell you how the weedless and normal prop compare as I haven't noticed any discernable difference between motors and I have yet to try switching the props. I'd be interested in seeing your results. I can tell you that my favourite and fastest 50's 10 hp is a 1953 Johnson with a weedless prop. However, its slightly lighter than the newer ones and only slightly faster. Hole shot is about the same on my boat.

 

[1730V]

Re: Wrong prop for '57 johnson 18hp?

I have a '57' 7 1/2 and have both a weedless and a brass 3 blade for.

The weedless does not perform as well. Very little difference, but noticeable on the same engine.